Low resistance crosspoint architecture

ABSTRACT

Methods, systems, and devices for a low resistance crosspoint architecture are described. A manufacturing system may deposit a thermal barrier material, followed by a first layer of a first conductive material, on a layered assembly including a patterned layer of electrode materials and a patterned layer of a memory material. The manufacturing system may etch a first area of the layered assembly to form a gap in the first layer of the first conductive material, the thermal barrier material, the patterned layer of the memory material, and the patterned layer of electrode materials. The manufacturing system may deposit a second conductive material to form a conductive via in the gap, where the conductive via extends to a height within the layered assembly that is above the thermal barrier material.

CROSS REFERENCE

The present Application for Patent is a divisional of U.S. patentapplication Ser. No. 16/684,520 by Venigalla et al., entitled “LOWRESISTANCE CROSSPOINT ARCHITECTURE” filed Nov. 14, 2019, assigned to theassignee hereof, and is expressly incorporated by reference in itsentirety herein.

BACKGROUND

The following relates generally to one or more memory systems and morespecifically to low resistance crosspoint architecture.

Memory devices are widely used to store information in variouselectronic devices such as computers, wireless communication devices,cameras, digital displays, and the like. Information is stored byprogramming different states of a memory device. For example, binarydevices most often store one of two states, often denoted by a logic 1or a logic 0. In other devices, more than two states may be stored. Toaccess the stored information, a component of the device may read, orsense, at least one stored state in the memory device. To storeinformation, a component of the device may write, or program, the statein the memory device.

Various types of memory devices exist, including magnetic hard disks,random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM),synchronous dynamic RAM (SDRAM), ferroelectric RAM (FeRAM), magnetic RAM(MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM),and others. Memory devices may be volatile or non-volatile. Non-volatilememory, e.g., FeRAM, may maintain their stored logic state for extendedperiods of time even in the absence of an external power source.Volatile memory devices, e.g., DRAM, may lose their stored state whendisconnected from an external power source. FeRAM may be able to achievedensities similar to volatile memory but may have non-volatileproperties due to the use of a ferroelectric capacitor as a storagedevice.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a memory device that supports lowresistance crosspoint architecture in accordance with examples asdisclosed herein.

FIG. 2 illustrates an example of a memory array that supports lowresistance crosspoint architecture in accordance with examples asdisclosed herein.

FIG. 3A through 6B illustrate examples of operations performed as partof manufacturing processes that support low resistance crosspointarchitecture in accordance with examples as disclosed herein.

FIGS. 7 and 8 show flowcharts illustrating a method or methods thatsupport low resistance crosspoint architecture in accordance withexamples as disclosed herein.

DETAILED DESCRIPTION

It may be desirable to form smaller memory cells, for example, toincrease the storage density of a memory array, decrease powerconsumption per memory cell, decrease manufacturing costs, etc. In somecases, memory cells may be formed in a three-dimensional (3D) structure(e.g., having one or more layers of memory where each layer extends intwo dimensions). The 3D structure may be formed above a substrate (e.g.,silicon wafer), and may be formed of layers of conductive material(e.g., for access lines such as word and bit lines), a memory material(e.g., chalcogenide), and other materials (e.g., electrode materials,dielectric materials). As memory cell structures become smaller,secondary effects from manufacturing processes (e.g., etch damage,material contamination, etc.) may have a greater impact on the structureand function of the final memory cell. Furthermore, an array of memorycells may be formed above a substrate and electrodes (e.g., vias) formedbetween the memory layers or other layers (e.g., substrate layers) madethrough the array of memory cells by performing an array terminationetch and deposition of additional materials (e.g., dielectric materials,via materials).

In some cases, a thermal barrier material may be present in between amemory stack containing a memory cell and an access line for that memorycell. The thermal barrier material may limit an amount of heat that maybe transferred from the memory stack to the access line and vice-versa,which may improve thermal properties and current response of the memorycell for programming SET or RESET states. However, thermal barriermaterials may have an associated resistance that may affect currentdelivery if within the electrode path. In some methods of manufacturing,thermal barrier materials may be also be present between a conductivevia used to transmit a signal to an access line and the access line. Assuch, when a signal is transmitted to the access line for a memory cell,the signal may pass through the thermal barrier material twice. However,as noted above, by passing through the thermal barrier twice, lesscurrent may be applied to the memory cell than if passing through thethermal barrier once.

To limit the amount of resistance that a thermal barrier material mayprovide, the thermal barrier material may be deposited prior toperforming an array termination etch used to deposit the conductive via.By providing the thermal barrier material before the array terminationetch occurs, the array termination etch may remove the thermal barriermaterial over a portion of the array used to deposit the conductive via.As such, the conductive via may interface with the access line directly(e.g., without the thermal barrier material being present).Additionally, a liner and cap material may be deposited and used tomitigate damage that occurs to the memory array during manufacturing.

Features of the disclosure are initially described in the context ofmemory devices as described with reference to FIGS. 1-2 . Features ofthe disclosure are described in the context of a manufacturing processas described with reference to FIGS. 3-6 . These and other features ofthe disclosure are further illustrated by and described with referenceto flowcharts that relate to low resistance crosspoint architecture asdescribed with references to FIGS. 7 and 8 .

FIG. 1 illustrates an example memory device 100 as disclosed herein.Memory device 100 may also be referred to as an electronic memoryapparatus. FIG. 1 is an illustrative representation of variouscomponents and features of the memory device 100. As such, it should beappreciated that the components and features of the memory device 100are shown to illustrate functional interrelationships, not their actualphysical positions within the memory device 100. In the illustrativeexample of FIG. 1 , the memory device 100 includes a 3D memory array102. The memory array 102 includes memory cells 105 that may beprogrammable to store different states. In some examples, each memorycell 105 may be programmable to store two states, denoted as a logic 0and a logic 1. In some examples, a memory cell 105 may be configured tostore more than two logic states. Although some elements included inFIG. 1 are labeled with a numeric indicator, other correspondingelements are not labeled, though they are the same or would beunderstood to be similar, in an effort to increase visibility andclarity of the depicted features.

The memory array 102 may include two or more two-dimensional (2D) memoryarrays 103 formed on top of one another. This may increase a quantity ofmemory cells that may be placed or created on a single die or substrateas compared with 2D arrays, which in turn may reduce production costs(e.g., cost per bit), or increase the performance of the memory device,or both. The memory array 102 may include two levels of memory cells 105and may thus be considered a 3D memory array; however, the quantity oflevels is not limited to two. Each level may be aligned or positioned sothat memory cells 105 may be aligned (exactly, overlapping, orapproximately) with one another across each level, forming a memory cellstack 145. In some cases, the memory cell stack 145 may include multiplememory cells laid on top of another while sharing a word line or a bitline for both as explained below. In some cases, the memory cells may bemulti-level memory cells configured to store more than one bit of datausing multi-level storage techniques.

In some examples, each row of memory cells 105 is connected to a wordline 110, and each column of memory cells 105 is connected to a bit line115. The term access lines may refer to word lines 110, bit lines 115,or combinations thereof. Word lines 110 and bit lines 115 may beperpendicular (or nearly so) to one another and may create an array ofmemory cells. As shown in FIG. 1 , the two memory cells 105 in a memorycell stack 145 may share a common conductive line such as a bit line115. That is, a bit line 115 may be in electronic communication with thebottom electrode of the upper memory cell 105 and the top electrode ofthe lower memory cell 105. Other configurations may be possible, forexample, a third layer may share a word line 110 with a lower layer. Ingeneral, one memory cell 105 may be located at the intersection of twoconductive lines such as a word line 110 and a bit line 115. Thisintersection may be referred to as a memory cell's address. A targetmemory cell 105 may be a memory cell 105 located at the intersection ofan energized access line 110 and bit line 115; that is, access line 110and bit line 115 may be energized (may have a voltage potential orcurrent flow) to read or write a memory cell 105 at their intersection.Other memory cells 105 that are in electronic communication with (e.g.,connected to) the same access line 110 or bit line 115 may be referredto as untargeted memory cells 105.

Electrodes may be coupled with a memory cell 105 and a word line 110 ora bit line 115. The term electrode may refer to an electrical conductor,and in some cases, may be employed as an electrical contact to a memorycell 105. An electrode may include a trace, wire, conductive line,conductive layer, or the like that provides a conductive path betweenelements or components of memory device 100. In some examples, a memorycell 105 may include a chalcogenide material positioned between a firstelectrode and a second electrode. One side of the first electrode may becoupled to a word line 110 and the other side of the first electrode tothe chalcogenide material. In addition, one side of the second electrodemay be coupled to a bit line 115 and the other side of the secondelectrode to the chalcogenide material. The first electrode and thesecond electrode may be the same material (e.g., carbon) or differentmaterials.

Operations such as reading and writing may be performed on memory cells105 by activating or selecting access line 110 and bit line 115. In someexamples, bit lines 115 may also be known digit lines 115. References toaccess lines, word lines, and bit lines, or their analogues, areinterchangeable without loss of understanding or operation. Activatingor selecting a word line 110 or a bit line 115 may include applying avoltage to the respective line. Word lines 110 and bit lines 115 may bemade of conductive materials such as metals (e.g., copper (Cu), aluminum(Al), gold (Au), tungsten (W), titanium (Ti)), metal alloys, carbon,conductively-doped semiconductors (e.g., polysilicon), or otherconductive materials, alloys, compounds, or the like.

Accessing memory cells 105 may be controlled through a row decoder 120and a column decoder 130. For example, a row decoder 120 may receive arow address from the memory controller 140 and activate the appropriateword line 110 based on the received row address. Similarly, a columndecoder 130 may receive a column address from the memory controller 140and activate the appropriate bit line 115. For example, memory array 102may include multiple word lines 110 for the top array, labeled WL_T1through WL_TM, multiple word lines 110 for the bottom array, labeledWL-B1 through WL_BM, and multiple digit lines 115, labeled BL_1 throughBL_N, where M and N depend on the array size. Thus, by activating a wordline 110 and a bit line 115, e.g., WL_T2 and BL_3, the memory cell 105at their intersection may be accessed. As discussed below in moredetail, accessing memory cells 105 may be controlled through a rowdecoder 120 and a column decoder 130 that may include one or more dopedmaterials (e.g., forming transistors) within or on a substrate coupledto the memory array 102.

Upon accessing, a memory cell 105 may be read, or sensed, by sensecomponent 125 to determine the stored state of the memory cell 105. Forexample, a voltage may be applied to a memory cell 105 (using thecorresponding word line 110 and bit line 115) and the presence of aresulting current may depend on the applied voltage and the thresholdvoltage of the memory cell 105. In some cases, more than one voltage maybe applied. Additionally, if an applied voltage does not result incurrent flow, other voltages may be applied until a current is detectedby sense component 125. By assessing the voltage that resulted incurrent flow, the stored logic state of the memory cell 105 may bedetermined. In some cases, the voltage may be ramped up in magnitudeuntil a current flow is detected. In other cases, predetermined voltagesmay be applied sequentially until a current is detected or a thresholdor limit voltage is applied. Likewise, a current may be applied to amemory cell 105 and the magnitude of the voltage to create the currentmay depend on the electrical resistance or the threshold voltage of thememory cell 105.

In some examples, a memory cell may be programmed by providing anelectric pulse to the cell, which may include a memory storage element.The pulse may be provided via a first access line (e.g., word line 110)or a second access line (e.g., bit line 115), or a combination thereof.In some cases, upon providing the pulse, ions may migrate within thememory storage element, depending on the polarity of the memory cell105. Thus, a concentration of ions relative to the first side or thesecond side of the memory storage element may be based at least in parton a polarity of a voltage between the first access line and the secondaccess line. In some cases, asymmetrically shaped memory storageelements may cause ions to be more crowded at portions of an elementhaving more area. Certain portions of the memory storage element mayhave a higher resistivity and thus may give rise to a higher thresholdvoltage than other portions of the memory storage element. Thisdescription of ion migration represents an example of a mechanism of thememory cell for achieving the results described herein. This example ofa mechanism should not be considered limiting. This disclosure alsoincludes other examples of mechanisms of the memory cell for achievingthe results described herein.

Sense component 125 may include various transistors or amplifiers todetect and amplify a difference in the signals, which may be referred toas sensing or latching. The detected logic state of memory cell 105 maythen be output through column decoder 130 as output 135. In some cases,sense component 125 may be part of a column decoder 130 or row decoder120. Or, sense component 125 may be connected to or in electroniccommunication with column decoder 130 or row decoder 120. The sensecomponent 125 may be associated either with column decoder 130 or rowdecoder 120.

A memory cell 105 may be set or written by activating the relevant wordline 110 and bit line 115 and at least one logic value may be stored inthe memory cell 105. Column decoder 130 or row decoder 120 may acceptdata, for example input/output 135, to be written to the memory cells105. In the case of a memory cell including a chalcogenide material, amemory cell 105 may be written to store a logic state in the memory cell105 by applying a first voltage to the memory cell 105 as part of theaccess operation based on coupling the first conductive line of thedecoder (e.g., row decoder 120 or column decoder 130) with the accessline (e.g., word line 110 or bit line 115).

The memory controller 140 may control the operation (e.g., read, write,re-write, refresh, discharge) of memory cells 105 through the variouscomponents, for example, row decoder 120, column decoder 130, and sensecomponent 125. In some cases, one or more of the row decoder 120, columndecoder 130, and sense component 125 may be co-located with the memorycontroller 140. Memory controller 140 may generate row and columnaddress signals to activate the desired word line 110 and bit line 115.Memory controller 140 may also generate and control various voltages orcurrents used during the operation of memory device 100.

The memory controller 140 may be configured to select the memory cell105 by applying a first voltage to the first conductive line of thedecoder (e.g., row decoder 120 or column decoder 130). In some cases,the memory controller 140 may be configured to couple the firstconductive line of the decoder with a word line (e.g., word line 110 orbit line 115) associated with the memory cell 105 based on selecting thememory cell 105. The memory controller 140 may be configured to applythe first voltage to the memory cell 105 based at least in part oncoupling the first conductive line of the decoder with the access line.

In some examples, the memory controller 140 may be configured to apply asecond voltage to a second conductive line of the decoder as part of theaccess operation. In some cases, the second voltage may cause the dopedmaterial to selectively couple the first conductive line of the decoderwith the access line associated with the memory cell 105. Applying thefirst voltage to the memory cell 105 may be based on applying the secondvoltage to the second conductive line. For example, the memorycontroller 140 may select the memory cell 105 based on an intersectionof the first voltage and the second voltage. In some cases, a signalapplied to the memory cell 105 as part of the access operation may havea positive polarity or a negative polarity.

In some examples, the memory controller 140 may receive a commandcomprising an instruction to perform the access operation on the memorycell 105 and identify an address of the memory cell 105 based onreceiving the command. In some cases, applying the second voltage to thesecond conductive line may be based on identifying the address. If theaccess operation is a read operation, the memory controller 140 may beconfigured to output a logic state stored in the memory cell 105 basedon applying the first voltage to the memory cell 105. If the accessoperation is a write operation, the memory controller 140 may beconfigured to store a logic state in the memory cell 105 based onapplying the first voltage to the memory cell 105. Although discussed asapplied by using a first voltage and a second voltage, it should beunderstood that current may be applied between the first conductive lineand second conductive line to perform the access operation, in somecases.

In some examples, each word line 110 and/or each bit line 115 may becoupled with a conductive via that couples the word line 110 and/or bitline 115 with a substrate upon which the memory device 100 rests.Generally, the conductive via may be formed by etching out a portion ofthe memory array 102 to form a gap and depositing the conductive viamaterial in the gap. However, methods of etching out the portion of thememory array 102 may damage memory cells 105 outside of the intendedcoverage of the gap, which may be referred to as tile or block damage.Methods of preventing tile or block damage may be described herein. Inaddition, methods of processing the memory array and conductive vias toreduce a resistance to word lines and/or bit lines are described herein.

FIG. 2 illustrates an example of a memory array that supports a memorydevice 200 in accordance with examples as disclosed herein. Memorydevice 200 may be an example of portions of memory array 102 describedwith reference to FIG. 1 . Memory device 200 may include a first arrayor deck 205 of memory cells that is positioned above a substrate 204 andsecond array or deck 210 of memory cells on top of the first array ordeck 205. Memory device 200 may also include word line 110-a and wordline 110-b, and bit line 115-a, which may be examples of word line 110and bit line 115, as described with reference to FIG. 1 . The first deck205 and the second deck 210 each may have one or more memory cell (e.g.,memory cell 220-a and memory cell 220-b, respectively). Although someelements included in FIG. 2 are labeled with a numeric indicator, othercorresponding elements are not labeled, though they are the same orwould be understood to be similar, in an effort to increase visibilityand clarity of the depicted features.

Memory cells of the first deck 205 may include first electrode 215-a,memory cell 220-a (e.g., including chalcogenide material), and secondelectrode 225-a. In addition, memory cells of the second deck 210 mayinclude a first electrode 215-b, memory cell 220-b (e.g., includingchalcogenide material), and second electrode 225-b. First electrode215-a, memory cell 220-a, and second electrode 225-a may form a firstmemory stack and first electrode 215-b, memory cell 220-b, and secondelectrode 225-b may form a second memory stack. The memory cells of thefirst deck 205 and second deck 210 may, in some examples, have commonconductive lines such that corresponding memory cells of each deck 205and 210 may share bit lines 115 or word lines 110 as described withreference to FIG. 1 . For example, first electrode 215-b of the seconddeck 210 and the second electrode 225-a of the first deck 205 may becoupled to bit line 115-a such that bit line 115-a is shared byvertically adjacent memory cells. In accordance with the teachingsherein, a decoder may be coupled with each deck if the memory device 200includes more than one deck. For example, a decoder may be coupled withfirst deck 205 and second deck 210. In some cases, the memory cells 220may be examples of phase-change memory cells or self-selecting memorycells.

The architecture of memory device 200 may be referred to as across-point architecture, in which a memory cell is formed at atopological cross-point between a word line and a bit line asillustrated in FIG. 2 . Such a cross-point architecture may offerrelatively high-density data storage with lower production costscompared to other memory architectures. For example, the cross-pointarchitecture may have memory cells with a reduced area and, resultantly,an increased memory cell density compared to other architectures. Forexample, the architecture may have a 4F2 memory cell area, where F isthe smallest feature size, compared to other architectures with a 6F2memory cell area, such as those with a three-terminal selectioncomponent. For example, DRAM may use a transistor, which is athree-terminal device, as the selection component for each memory celland may have a larger memory cell area compared to the cross-pointarchitecture. In some cases, a cross-point architecture may be formed bytwo consecutive etches or cuts with patterns along orthogonaldirections.

While the example of FIG. 2 shows two memory decks, other configurationsare possible. In some examples, a single memory deck of memory cells maybe constructed above a substrate 204, which may be referred to as atwo-dimensional memory. In some examples, three or four memory decks ofmemory cells may be configured in a similar manner in athree-dimensional cross point architecture.

In some examples, one or more of the memory decks may include a memorycell 220 that includes chalcogenide material. The memory cell 220 may,for example, include a chalcogenide glass such as, for example, an alloyof selenium (Se), tellurium (Te), arsenic (As), antimony (Sb), carbon(C), germanium (Ge), and silicon (Si). In some examples, a chalcogenidematerial having primarily Se, As, and Ge may be referred to asSAG-alloy. In some examples, SAG-alloy may include Si and suchchalcogenide material may be referred to as SiSAG-alloy. In someexamples, the chalcogenide glass may include additional elements such ashydrogen (H), oxygen (O), nitrogen (N), chlorine (CO, or fluorine (F),each in atomic or molecular forms.

In some examples, a memory cell 220 including a chalcogenide materialmay be programmed to a logic state by applying a first voltage or afirst current. By way of example, when a particular memory cell 220 isprogramed, elements within the cell may separate, causing ion migration.Ions may migrate towards a particular electrode, depending on thepolarity of the voltage applied to the memory cell. For example, in amemory cell 220, ions may migrate towards the negative electrode. Thememory cell may then be read by applying a voltage across the cell tosense. The threshold voltage seen during a read operation may be basedon the distribution of ions in the memory cell and the polarity of theread pulse.

For example, if a memory cell has a given distribution of ions, thethreshold voltage detected during the read operation may be differentfor a first read voltage with a first polarity than it is with a secondread voltage having a second polarity. Depending on the polarity of thememory cell, this concentration of migrating ions may represent a logic“1” or logic “0” state. This description of ion migration represents anexample of a mechanism of the memory cell for achieving the resultsdescribed herein. This example of a mechanism should not be consideredlimiting. This disclosure is also applicable to other examples ofmechanisms of the memory cell for achieving the results describedherein.

In some cases, a first voltage may be applied to a first conductive lineof a decoder as part of an access operation of the memory cell 220. Uponapplying the first voltage, the first conductive line may be coupledwith the access line (e.g., word line 110-a, word line 110-b, or bitline 115-a) associated with the memory cell 220. For example, the firstconductive line may be coupled with the access line based on a dopedmaterial of the decoder which extends between the first conductive lineand the access line in a first direction.

In some examples, the first voltage may be applied to the memory cell220 based on coupling the first conductive line of the decoder with theaccess line. The decoder may include one or more transistors selectivelycoupling the first conductive line and the access line of the memorydevice 200. In some cases, the decoder may be formed in the substrate204.

In some examples, a thermal barrier may be present in between anelectrode and an access line. For instance, a thermal barrier may bepresent in between electrode 215-a and word line 110-a; betweenelectrode 225-a and bit line 115-a; between electrode 215-b and bit line115-a; between electrode 225-b and word line 110-b; or a combinationthese locations. The thermal barrier material may be configured toreduce diffusion of heat from a memory cell 220 onto a word line 110 ora bit line 115, or vice-versa. The thermal barrier may be a tungstensilicon nitride (WSiN) material.

In some examples, a word line 110 and/or a bit line 115 may be coupledwith a conductive via that couples the word line 110 and/or the bit line115 with the substrate 204. In some cases, a conductive via may becoupled with word lines 110 or bit lines 115 from different decks. Forinstance, in the present example, a conductive via may be coupled withword line 110-a in deck 205 and word line 110-b in deck 210. Accordingto techniques described herein, the thermal barrier material may beformed between the electrode material and a word line or a bit linewithout also being between the conductive via and the word line or bitline.

FIGS. 3A through 6B illustrate manufacturing processes that includeperforming a series of operations on a layered assembly of materials toform a memory array including a conductive via. These figures illustrateexamples of intermediate structures that may be formed by performingoperations of the manufacturing processes on a layered assembly ofmaterials. The structures illustrated in FIGS. 3A, 3B, and 3C mayrepresent initial or partial processing steps on the layered assembly.The structures illustrated in FIGS. 4A, 4B, and 4C may represent a firstset of processing steps performed after the initial processing steps andthe structures illustrated in FIGS. 5A, 5B, 5C, 6A, and 6B may representa second set of processing steps performed after the initial processingsteps. Together, FIGS. 3A, 3B, 3C, 4A, 4B, and 4C may represent a firstmanufacturing process and FIGS. 3A, 3B, 3C, 5A, 5B, 5C, 6A, and 6B mayrepresent a second manufacturing process. In some cases, the first orsecond manufacturing processes may include combining various operations,altering the sequence of operations, eliminating one or more steps ofthese operations, or any combination thereof.

FIGS. 3A, 3B, and 3C illustrate cross-sectional views of layeredassemblies of materials 300-a, 300-b, and 300-c that support lowresistance crosspoint architecture in accordance with examples asdisclosed herein.

In FIG. 3A, memory stacks 305 may be separated from each other bydielectric material 310. Memory stack 305 may be composed of electrodematerials (e.g., electrodes 215 and 225 as described with reference toFIG. 2 ) and memory materials (e.g., memory cell 220 as described withreference to FIG. 2 ). Dielectric materials 310 may be configured toprovide structure while limiting an amount of charge that may betransferred between memory stacks 305.

In some cases, the arrangement of materials on each memory stack 305 maybe the same for each memory stack 305. For instance, if a first memorystack 305 has a bottom electrode material, a memory material above thebottom electrode material, and a top electrode material above the memorymaterial, a second adjacent memory stack may have a corresponding bottomelectrode material, a corresponding memory material, and a correspondingtop electrode material. The set of materials that correspond to eachother among memory stacks 305 may be considered a patterned layer. Forinstance, the set of bottom electrodes may be considered a firstpatterned layer; the set of memory materials may be considered a secondpatterned layer; and the set of top electrodes may be considered a thirdpatterned layer. The individual materials of memory stack 305 are notillustrated in FIGS. 3A to 6B for the sake of clarity.

Additionally, a hard mask (HM) 315 may be used for patterning at leastpart of memory stacks 305, and after a first planarization step (e.g.,via chemical mechanical planarization (CMP)) may be approximately at alevel of the dielectric material 310 between memory stacks 305. In somecases, HMs 315 may be composed of a nitride material.

In FIG. 3B, a manufacturing system may perform another processing stepto etch HMs 315 (e.g., a second CMP step) and at least a portion ofdielectric materials 310 away, which may expose the tops of the memorystacks 305. The dielectric material 310 may have a higher rate ofmaterial removal than the HM 315 and memory stack 305, and may have asmaller height than the memory stacks 305 after the processing step toetch HMs 315. In some cases, the termination process to remove the HMs315 may be a wet process that does not result in substantial socketdishing.

In FIG. 3C, a manufacturing system may deposit a thermal barriermaterial 320 onto the memory stacks 305 and the dielectric materials310. The manufacturing system may deposit the thermal barrier material320 such that the exposed tops and the exposed sides of the memorystacks 305 are fully covered. The manufacturing system may then deposita conductive material 325 on top of the thermal barrier material 320.The manufacturing system may deposit the conductive material 325 suchthat the conductive material 325 has a relatively uniform surface on thetop, or may perform processing (e.g., CMP) to produce the relativelyuniform surface. In such cases, the thickness of the conductive material325 may vary depending on whether the conductive material is over amemory stack 305 or a dielectric material 310.

FIGS. 4A, 4B, and 4C illustrate cross-sectional views of layeredassemblies of materials 400-a, 400-b, and 400-c that support lowresistance crosspoint architecture in accordance with examples asdisclosed herein. In some cases, FIGS. 4A, 4B, and 4C may representsteps undertaken after the steps represented by FIGS. 3A, 3B, and 3Chave taken place.

In FIG. 4A, a manufacturing system may etch at least some of the memorystacks 305 and the dielectric material 310 away at a first area of thelayered assembly to form a gap 405. In the same processing step, themanufacturing system may etch at least a portion of the thermal barriermaterial 320 and the conductive material 325. In some cases, themanufacturing system match etch one or multiple decks of memory stacks(e.g., the manufacturing system match etch one or more decks or all ofthe way to a substrate). FIG. 4A may illustrate the result of processingsteps after FIG. 3C including deposition and patterning of a mask layer,and performing an etch with the patterned mask layer to remove thematerials from the gap 405.

The presence of conductive material 325 may assist in preventing socketdishing at the interface between the array 425 and the gap 405. Forexample, where the conductive material 325 is not present whenperforming the etching, the etching may occur faster at the interfacebetween the array 425 and the gap 405 due to increased CMP loading.Thus, the manufacturing process may cut into memory stacks 305 outsideof the intended gap 405, which may be referred to as socket dishing.However, the planarization step to remove the mask over conductivematerial 325 may produce less socket dishing due to the different maskmaterials and increase in tolerance of the planarization (e.g., due tothe thickness of the conductive material 325). The reduced socketdishing may reduce the possibility of damage impacting operation of thearray or increase the number of layers that can be formed.

In FIG. 4B, the manufacturing system may deposit a dielectric material410 in the gap 405. For example, from the assembly shown in FIG. 4A,deposition of the dielectric material 410 may be followed by aplanarization step (e.g., CMP) to remove the dielectric material 410over the array 425. The dielectric material 410 may be configured toprovide structure and insulate the memory stack 305. After theplanarization, the dielectric material 410 may have a top surface thatis co-planar or substantially co-planar with the conductive material325. In some cases, the conductive material 325 may serve to increasethe tolerance of the planarization step where the thermal barriermaterial 320 is deposited prior to the termination etch to create thegap 405. For example, the conductive material 325 may be substantiallythicker than the thermal barrier material 320. Without the conductivematerial 325 over the thermal barrier, stopping the planarization at orpartially into the thermal barrier 320 may be challenging. For example,if the planarization step does not take off all of the dielectricmaterial 410 over the array 425, the conductivity through the thermalbarrier may be compromised. Meanwhile, if the planarization step takesoff excess amounts of the thermal barrier material, the performance ofthe memory cells may be compromised. However, performing theplanarization with the conductive material 325 may allow a greatertolerance for stopping the planarization within the thickness of theconductive material 325.

In FIG. 4C, the manufacturing system may etch the dielectric material410 to form a gap or hole (e.g., using one or more mask steps). The gapmay extend through the dielectric material 410 to, for example, asubstrate below the dielectric material 410. The manufacturing systemmay deposit a conductive via material 415 in the gap such that the viamaterial 415 extends through the dielectric material 410. The conductivevia material 415 may have a surface in line with the dielectric material410. In some cases, the conductive via material 415 may extend to aheight within the layered assembly that is above the thermal barriermaterial 320.

Additionally, the manufacturing system may deposit a conductive material420 on the conductive material 325, the dielectric material 410, and theconductive via material 415. The conductive material 420 may couple theconductive via material 415 with the memory stacks 305 via theconductive material 325. The conductive materials 325 and 420 may becomposed of a same material or may be composed of different materials.Together, conductive materials 325 and 420 may form an access line(e.g., a word line 110 or a bit line 115). In some cases, conductivematerial 420 may be composed of tungsten. In some cases, themanufacturing system may buff the conductive material 325 prior todeposition of the conductive material 420. Buffing may involve smoothingout the surface of the conductive material 325, and may assist inadherence of the conductive material 420 or conductivity betweenconductive material 325 and conductive material 420. In some cases,conductive material 325 may be composed of tungsten.

In some cases, where the steps of FIG. 3C do not occur (e.g., where thethermal barrier material 320 and the conductive material 325 are notdeposited), the thermal barrier material 320 may be deposited after theconductive via material 415 is deposited but before the conductivematerial 420 is deposited. In such cases, the top surface of thedielectric material 410 and the conductive via material 415 may be inline with the memory stacks 305. However, by forming a memory device inthis fashion, the thermal barrier material may create unnecessaryresistance between the conductive via material 415 and the conductivematerial 420. Such extra resistance may limit the current which maydelivered from the conductive via material 415. As such, by depositingthe thermal barrier material 320 before the etching at FIG. 4A occurs,the manufacturing system may enable the conductive material 420 tointerface with the conductive via material 415, directly.

FIGS. 5A, 5B, and 5C illustrate cross-sectional views of layeredassemblies of materials 500-a, 500-b, and 500-c that support lowresistance crosspoint architecture in accordance with examples asdisclosed herein. In some cases, FIGS. 5A, 5B, and 5C may representsteps undertaken after the steps represented by FIGS. 3A, 3B, and 3Chave taken place

In FIG. 5A, the manufacturing system may deposit a cap material 505 overthe conductive material 325. The cap material 505 may protect thethermal barrier material 320, the conductive material 325, and thememory stacks 305 during processing. In some cases, the manufacturingsystem may buff the conductive material 325 prior to deposition of thecap material 505. Buffing may flatten the topography of the conductivematerial 325 and may enable the manufacturing system to deposit capmaterial 505 on a uniform surface.

In FIG. 5B, the manufacturing system may etch at least some of thememory stacks 305 and the dielectric material 310 away at a first areaof the layered assembly to form a gap 530. In the same processing step,the manufacturing system may etch at least a portion of the thermalbarrier material 320, the conductive material 325, and the cap material505. Additionally, the manufacturing system may deposit a liner material510 over the cap material 505 and in the gap 530. The liner material 510may deposit over the exposed portions of the liner material 510, gap 530(e.g., substrate), and sidewall of the array 525 (e.g., memory stack ordielectric). Thus, the liner material 510 may have a first horizontalportion over the cap material 505, a second horizontal portion over thegap 530, and a vertical portion that is in contact with an end of thecap material 505, an end of the conductive material 325, and an end ofthe thermal barrier material 320. The vertical portion of the linermaterial 510 may protect an adjacent memory stack 305, the cap material505, the conductive material 325, the thermal barrier material 320 or acombination of these during additional processing or during operation(e.g., by additional insulative properties). The liner material 510 may,for example, have a higher dielectric constant than a dielectricmaterial used to fill the gap 530.

Additionally, the vertical portion may be in contact with the memorystack 305. In some cases, the vertical portion may adjoin the first andsecond horizontal portions. The liner material 510 may be composed ofthe same material as the cap material 505 or may be composed of adifferent material. For instance, both the cap material 505 and theliner material 510 may be composed of a nitride-like material.Alternatively the cap material 505 may be composed of a nitride materialand the liner material 510 may be composed of a nitride-like materialdifferent from the cap material 510.

The manufacturing system may use a two-step planarization or removalprocess to fill the gap 530 and planarize the assembly after depositionof a dielectric material 515. Initially, starting from FIG. 5A, thedielectric material 515 may be deposited over both the array 525 and gap530 (not shown). A first planarization step may be used designed to stopon the cap material 505. The first planarization step may use a firstslurry (e.g., an oxide slurry). The first planarization step may resultin the assembly shown in FIG. 5C. Thus, the dielectric material 515 isshown over the second horizontal portion of the liner material 510 andfilling the gap to approximately the height of the cap material 505 (orthe portion of the cap material 505 that remains after the planarizationstep stops at the cap material 505).

After depositing the dielectric material 515 and performing the firstplanarization process, the manufacturing system may etch the dielectricmaterial 515 and a portion of the liner material 510 to form a gap orhole. The manufacturing system may deposit a conductive via material 520in the gap or hole such that the via material 520 extends through thedielectric material 515. In some cases, a top surface of the conductivevia material 520 may be in line with dielectric material 515. In somecases, the conductive via material 520 may extend to a height within thelayered assembly that is above the thermal barrier material.

Subsequently, the manufacturing system may use a second planarizationstep to remove the cap material 505 to result in layered assembly ofmaterials 600-a shown in FIG. 6A. The second planarization step may usedifferent processing features than the first planarization step (e.g., asecond, different slurry than the first slurry, a different pad). Thesecond planarization process may be formulated to stop on the conductivematerial 325.

After the second planarization process is completed, a top surface ofconductive material 325, a top surface of the vertical portion of theliner material 510, a top surface of dielectric material 515, and a topsurface of conductive via material 520 may be approximately co-planarwith each other.

The manufacturing system may deposit a conductive material 605 on top ofthe conductive material 325, the vertical portion of the liner material510, the dielectric material 515, and the conductive via material 520 toresult in layered assembly of materials 600-b shown in FIG. 6B. Theconductive material 605 may couple the conductive via material 520 withthe memory stacks 305 via the conductive material 325. The conductivematerials 325 and 605 may be composed of a same material or may becomposed of different materials. If conductive materials 325 and 605 arecomposed of the same material, conductive material 325 may be consideredto be a first layer and conductive material 605 may be considered to bea second layer. Together, conductive materials 325 and 605 may form anaccess line (e.g., a word line 110 or a bit line 115). In some cases,conductive material 605 may be composed of tungsten. In some cases, themanufacturing system may buff the conductive material 325 prior todeposition of the conductive material 605. Buffing may involve smoothingout the surface of the conductive material 325, and may assist inadherence of the conductive material 605 or conductivity betweenconductive material 325 and conductive material 605.

Similar to FIG. 4 , depositing the thermal barrier material 320 beforeetching to form the gap for the dielectric material 515 may enable theconductive material 605 to interface directly with the conductive viamaterial 520. If the thermal barrier material 320 had been depositedafter etching to form the gap, the thermal barrier material 320 may bein between the conductive material 605 and the conductive via material520, which may increase the resistance between the conductive material605 and the conductive via material 520. As such, for a particularvoltage, the amount of current may be increased for the former case ascompared to the latter case.

Additionally, in some cases, the steps of FIGS. 3B and 3C may not occur.As such, the HMs 315 of FIG. 3A may not be removed and the thermalbarrier material 320 and the conductive material 325 may not bedeposited. In such cases, a cap material 505 may be deposited overdielectric materials 310 and HMs 315, such as in FIG. 5A; a linermaterial 510 may be deposited and a gap may be etched such as describedin FIG. 5B; and a dielectric material 515 and a conductive via material520 may be deposited as in FIG. 5C. After depositing the conductive viamaterial 520, the horizontal portion of the liner material 510 over thecap material 505, the cap material 505, and the HMs 315 may be etchedout (e.g., via CMP).

While the etching processes are occurring, the materials may beassembled such that the cap material 505 has thinner overburden and moreCMP loading. As such, open areas (i.e., sockets) in the memory die mayclear earlier, which may cause the sockets to be recessed, dished, orphysically damaged before the HMs 315 over the array or tile are yet toclear completely. The methods described herein avoid this situation byetching out the HMs 315 prior to socket formation, which may preventsockets from forming. If the termination process described in FIG. 3B isa wet process, the cap material 505 may be a nitride-like material,which may be a wet process selective film. Alternatively, to mitigaterisks associated with changing the cap film, the cap material 505 may becomposed of a nitride material. In either case, current delivery may beimproved due to the lack of a thermal barrier to separate the conductivematerial 605 from the conductive via material 520. Additionally oralternatively, a process margin may be improved due to the conductivematerial 325 acting as stop layer for when cap material 505 is removed(e.g., at FIGS. 5C and 6A). As such, the methods disclosed herein mayhave a healthier process window as compared to the case described abovewhere the steps of FIGS. 3B and 3C do not occur.

Generally, the processes as described herein may enable a smaller diesize, as the processes described herein may limit tile damage thatoccurs at smaller scales. Additionally or alternatively, the processesdescribed herein may decrease a size of sockets or may prevent theformation of sockets completely, which may lower a chance that tiledamage will occur. Additionally or alternatively, the processesdescribed herein may provide fewer dummy line opportunities.

FIG. 7 shows a flowchart illustrating a method or methods 700 thatsupports low resistance crosspoint architecture in accordance withexamples as disclosed herein. The operations of method 700 may beimplemented by a manufacturing system or one or more controllersassociated with a manufacturing system. In some examples, one or morecontrollers may execute a set of instructions to control one or morefunctional elements of the manufacturing system to perform the describedfunctions. Additionally or alternatively, one or more controllers mayperform aspects of the described functions using special-purposehardware.

At 705, the method 700 may include depositing a thermal barrier materialon a layered assembly including a patterned layer of electrode materialsand a patterned layer of a memory material. The operations of 705 may beperformed according to the methods described herein.

At 710, the method 700 may include depositing, on the layered assemblyover the thermal barrier material, a first layer of a first conductivematerial. The operations of 710 may be performed according to themethods described herein.

At 715, the method 700 may include etching, at a first area of thelayered assembly, through the layered assembly to form a gap in thefirst layer of the first conductive material, the thermal barriermaterial, the patterned layer of the memory material, and the patternedlayer of electrode materials. The operations of 715 may be performedaccording to the methods described herein.

At 720, the method 700 may include depositing a second conductivematerial to form a conductive via in the gap, the conductive viaextending to a height within the layered assembly that is above thethermal barrier material. The operations of 720 may be performedaccording to the methods described herein.

In some examples, an apparatus as described herein may perform a methodor methods, such as the method 700. The apparatus may include features,means, or instructions (e.g., a non-transitory computer-readable mediumstoring instructions executable by a processor) for depositing a thermalbarrier material on a layered assembly including a patterned layer ofelectrode materials and a patterned layer of a memory material,depositing, on the layered assembly over the thermal barrier material, afirst layer of a first conductive material, etching, at a first area ofthe layered assembly, through the layered assembly to form a gap in thefirst layer of the first conductive material, the thermal barriermaterial, the patterned layer of the memory material, and the patternedlayer of electrode materials, and depositing a second conductivematerial to form a conductive via in the gap, the conductive viaextending to a height within the layered assembly that is above thethermal barrier material.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a second layer of the first conductive material over thefirst layer of the first conductive material and the conductive via,where the second layer couples the first layer of the first conductivematerial with the conductive via.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions for buffingthe first conductive material prior to depositing the second layer ofthe first conductive material.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a dielectric material in the gap, where the conductive viaextends through the dielectric material in the gap.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a liner material over the layered assembly prior todepositing the dielectric material.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions forperforming a first planarization process with a first slurry, the firstplanarization process removing a first portion of the liner material.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions forperforming a second planarization process with a second slurry, thesecond planarization process removing a second portion of the linermaterial.

Some examples of the method 700 and the apparatus described herein mayfurther include operations, features, means, or instructions fordepositing a cap material over the layered assembly prior to etchingthrough the layered assembly at the first area.

FIG. 8 shows a flowchart illustrating a method or methods 800 thatsupports low resistance crosspoint architecture in accordance withexamples as disclosed herein. The operations of method 800 may beimplemented by a manufacturing system or one or more controls associatedwith a manufacturing system. In some examples, one or more controllersmay execute a set of instructions to control one or more functionalelements of the manufacturing system to perform the described functions.Additionally or alternatively, one or more controllers may performaspects of the described functions using special-purpose hardware.

At 805, the method 800 may include etching through a first area of alayered assembly to form a gap in the layered assembly, where thelayered assembly includes a first layer including an electrode material,a second layer including a memory material, a third layer including athermal barrier material, and a fourth layer including a firstconductive material. The operations of 805 may be performed according tothe methods described herein.

At 810, the method 800 may include depositing a dielectric materialwithin the gap in the layered assembly. The operations of 810 may beperformed according to the methods described herein.

At 815, the method 800 may include etching one or more holes through thedielectric material. The operations of 815 may be performed according tothe methods described herein.

At 820, the method 800 may include depositing a second conductivematerial to form conductive vias in the one or more holes. Theoperations of 820 may be performed according to the methods describedherein.

At 825, the method 800 may include depositing a fifth layer includingthe first conductive material over the layered assembly, a portion ofthe fifth layer in contact with a conductive via and at least part ofthe fourth layer. The operations of 825 may be performed according tothe methods described herein.

A memory device prepared by a process is described. The process mayinclude the steps of etching through a first area of a layered assemblyto form a gap in the layered assembly, where the layered assemblyincludes a first layer including an electrode material, a second layercomprising a memory material, a third layer comprising a thermal barriermaterial, and a fourth layer comprising a first conductive material;depositing a dielectric material within the gap in the layered assembly;etching one or more holes through the dielectric material; depositing asecond conductive material to form conductive vias in the one or moreholes; and depositing a fifth layer comprising the first conductivematerial over the layered assembly, a portion of the fifth layer incontact with a conductive via and at least part of the fourth layer.

In some examples, the process may further include the steps ofdepositing a cap material over the layered assembly prior to etchingthrough the first area. In some examples, the process may furtherinclude the steps of depositing a liner material over the layeredassembly prior to depositing the dielectric material. In some examples,the cap material and the liner material may be the same material. Insome examples, the cap material and the liner material may be differentmaterials. In some examples, the process may further include the stepsof buffing the first conductive material prior to depositing the fifthlayer.

It should be noted that the methods described herein are possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Furthermore, portions from two or more of the methods may be combined.

An apparatus is described. The apparatus may include a first portion ofa memory device including a first patterned layer including an electrodematerial; a second patterned layer including a memory material; and athird patterned layer including a conductive material and a thermalbarrier material. The apparatus may include a second portion of thememory device including a fourth patterned layer including a set of viasthrough a dielectric material, the fourth patterned layer extending to aheight that exceeds a height of the thermal barrier material in thethird patterned layer and a fifth patterned layer including theconductive material, wherein a thickness of the conductive material inthe fifth patterned layer is less than a thickness of the conductivematerial in the third patterned layer.

In some examples, the memory device may include a liner material incontact with the first patterned layer, the second patterned layer, andthe third patterned layer, where the liner material forms a separatingbarrier between the first portion of the memory device and the secondportion of the memory device. In some examples, the liner materialincludes a first portion extending in a first direction and a secondportion extending in a second direction, where the first portion is incontact with the first patterned layer, the second patterned layer, andthe third patterned layer, and where the second portion is punctured bythe set of vias.

In some examples, a patterned member of the conductive material is indirect contact with a via of the fourth patterned layer. In someexamples, the thermal barrier material includes tungsten siliconnitride. In some examples, the conductive material includes tungsten.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof. Some drawings may illustrate signals as a single signal;however, it will be understood by a person of ordinary skill in the artthat the signal may represent a bus of signals, where the bus may have avariety of bit widths.

The terms “electronic communication,” “conductive contact,” “connected,”and “coupled” may refer to a relationship between components thatsupports the flow of signals between the components. Components areconsidered in electronic communication with (or in conductive contactwith or connected with or coupled with) one another if there is anyconductive path between the components that can, at any time, supportthe flow of signals between the components. At any given time, theconductive path between components that are in electronic communicationwith each other (or in conductive contact with or connected with orcoupled with) may be an open circuit or a closed circuit based on theoperation of the device that includes the connected components. Theconductive path between connected components may be a direct conductivepath between the components or the conductive path between connectedcomponents may be an indirect conductive path that may includeintermediate components, such as switches, transistors, or othercomponents. In some examples, the flow of signals between the connectedcomponents may be interrupted for a time, for example, using one or moreintermediate components such as switches or transistors.

The term “coupling” refers to condition of moving from an open-circuitrelationship between components in which signals are not presentlycapable of being communicated between the components over a conductivepath to a closed-circuit relationship between components in whichsignals can be communicated between components over the conductive path.When a component, such as a controller, couples other componentstogether, the component initiates a change that allows signals to flowbetween the other components over a conductive path that previously didnot permit signals to flow.

The term “isolated” refers to a relationship between components in whichsignals are not presently capable of flowing between the components.Components are isolated from each other if there is an open circuitbetween them. For example, two components separated by a switch that ispositioned between the components are isolated from each other when theswitch is open. When a controller isolates two components from oneanother, the controller affects a change that prevents signals fromflowing between the components using a conductive path that previouslypermitted signals to flow.

The term “layer” or “level” used herein refers to a stratum or sheet ofa geometrical structure (e.g., relative to a substrate). Each layer orlevel may have three dimensions (e.g., height, width, and depth) and maycover at least a portion of a surface. For example, a layer or level maybe a three dimensional structure where two dimensions are greater than athird, e.g., a thin-film. Layers or levels may include differentelements, components, and/or materials. In some examples, one layer orlevel may be composed of two or more sublayers or sublevels.

As used herein, the term “electrode” may refer to an electricalconductor, and in some examples, may be employed as an electricalcontact to a memory cell or other component of a memory array. Anelectrode may include a trace, wire, conductive line, conductive layer,or the like that provides a conductive path between elements orcomponents of the memory array.

The devices discussed herein, including a memory array, may be formed ona semiconductor substrate, such as silicon, germanium, silicon-germaniumalloy, gallium arsenide, gallium nitride, etc. In some examples, thesubstrate is a semiconductor wafer. In other cases, the substrate may bea silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG)or silicon-on-sapphire (SOS), or epitaxial layers of semiconductormaterials on another substrate. The conductivity of the substrate, orsub-regions of the substrate, may be controlled through doping usingvarious chemical species including, but not limited to, phosphorous,boron, or arsenic. Doping may be performed during the initial formationor growth of the substrate, by ion-implantation, or by any other dopingmeans.

A switching component or a transistor discussed herein may represent afield-effect transistor (FET) and comprise a three terminal deviceincluding a source, drain, and gate. The terminals may be connected toother electronic elements through conductive materials, e.g., metals.The source and drain may be conductive and may comprise a heavily-doped,e.g., degenerate, semiconductor region. The source and drain may beseparated by a lightly-doped semiconductor region or channel. If thechannel is n-type (i.e., majority carriers are electrons), then the FETmay be referred to as a n-type FET. If the channel is p-type (i.e.,majority carriers are holes), then the FET may be referred to as ap-type FET. The channel may be capped by an insulating gate oxide. Thechannel conductivity may be controlled by applying a voltage to thegate. For example, applying a positive voltage or negative voltage to ann-type FET or a p-type FET, respectively, may result in the channelbecoming conductive. A transistor may be “on” or “activated” when avoltage greater than or equal to the transistor's threshold voltage isapplied to the transistor gate. The transistor may be “off” or“deactivated” when a voltage less than the transistor's thresholdvoltage is applied to the transistor gate.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details toproviding an understanding of the described techniques. Thesetechniques, however, may be practiced without these specific details. Insome instances, well-known structures and devices are shown in blockdiagram form to avoid obscuring the concepts of the described examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the above description may berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a digital signal processor (DSP), an ASIC, afield-programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any processor, controller,microcontroller, or state machine. A processor may also be implementedas a combination of computing devices (e.g., a combination of a DSP anda microprocessor, multiple microprocessors, one or more microprocessorsin conjunction with a DSP core, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described above can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be apparent to those skilled in the art, and the generic principlesdefined herein may be applied to other variations without departing fromthe scope of the disclosure. Thus, the disclosure is not limited to theexamples and designs described herein but is to be accorded the broadestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A memory device, comprising: a first portion,comprising: a first patterned layer comprising an electrode material; asecond patterned layer comprising a memory material; and a thirdpatterned layer comprising a thermal barrier material; a second portioncomprising: a fourth patterned layer comprising a plurality of viasthrough a dielectric material, the fourth patterned layer extending to aheight that exceeds a height of the thermal barrier material in thethird patterned layer; and a conductive material over the first portionand the second portion, wherein a thickness of the conductive materialover the first portion is larger than a thickness of the conductivematerial over the second portion, and wherein the conductive material isin contact with the dielectric material of the fourth patterned layer.2. The memory device of claim 1, further comprising: a liner material incontact with the first patterned layer, the second patterned layer, andthe third patterned layer, wherein the liner material forms a separatingbarrier between the first portion of the memory device and the secondportion of the memory device.
 3. The memory device of claim 2, whereinthe liner material comprises a first portion extending in a firstdirection and a second portion extending in a second direction, whereinthe first portion is in contact with the first patterned layer, thesecond patterned layer, and the third patterned layer, and wherein thesecond portion is punctured by the plurality of vias.
 4. The memorydevice of claim 1, wherein a patterned member of the conductive materialis in direct contact with a via of the fourth patterned layer.
 5. Thememory device of claim 1, wherein the thermal barrier material comprisestungsten silicon nitride.
 6. The memory device of claim 1, wherein theconductive material comprises tungsten.